JPH0760640B2 - Microwave tube - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a microwave tube such as a traveling wave tube using an electron beam, and particularly to the structure of a collector portion thereof.

[Conventional technology]

Low power consumption is required for microwave tubes used for transmitters such as relay stations of microwave radio communication lines and satellite communication ground stations. Recently, the power of each part of the equipment other than the microwave tube has become low power consumption due to the IC, so the demand for the microwave tube has become much more severe.

The microwave tube of the present invention is composed of an electron gun part, a high frequency circuit part, a collector part, and a focusing magnetic field device part for focusing an electron beam, but in response to the above demand for low power consumption, A multi-stage potential drop collector has been devised for the collector part that has the least influence on the high frequency characteristics.

When the electron beam interacts with the high-frequency circuit, the coupling states thereof are different from each other, and the kinetic energy of the electron beam after the interaction has a distribution and velocity dispersion. In order for the electron beam having such a velocity distribution to be captured by the collector, the potential must be sufficient to capture the slowest electron beam group. However, since it is possible to capture an electron beam group earlier than that, even if the potential is originally lower than the above potential, the collector is divided into several stages in the multi-stage potential decreasing collector, and the potential is gradually lowered from the incident end of the electron beam. By going, the electron beam group is velocity-classified and captured. As a result, the collector potential is effectively lowered, and the collector loss can be reduced.

[Problems to be solved by the invention]

Even in the above-described multi-stage potential-decreasing collector, when the potential at the incident end is further reduced, a part of the primary electron beam group which does not have a velocity sufficient to be trapped by the collector and secondary electrons generated on the inner surface of the collector are It goes backward from the collector to the high-frequency circuit section having a higher potential, acts on the high-frequency circuit section, adversely affects the transmission characteristics such as amplitude distortion and phase distortion, and becomes abnormal oscillation and unstable operation. Therefore, even in the multi-stage potential decreasing collector, there is a limit in reducing the maximum potential.

In order to prevent retrograde electrons due to a decrease in collector potential in a multi-stage potential decreasing collector or a general collector, a deflection magnetic field is applied inside the collector perpendicularly to the tube axis in order to prevent retrograde electrons due to a decrease in collector potential. There is also a possibility to take a measure to prevent the retrograde to the high frequency circuit section by bending. However, in the case of a forced air-cooled microwave tube, etc., a radiator blade made of copper with good thermal conductivity is radially brazed to the outer circumference of the collector, so that the deflection magnetic field is applied from the outside of the radiator blade. Even if is applied, the deflection magnetic field generated inside the collector becomes weak in inverse proportion to the square of the distance because of the radial distance of the heat radiating blade. Therefore, there is a drawback that the retrograde electron preventing effect becomes small.

An object of the present invention is to provide a collector having a structure in which a collector portion can be lowered and collector loss can be reduced by effectively preventing retrograde electrons generated by the collector potential lowering in a multistage potential lowering collector or a general collector. To provide a wave tube.

[Means for solving problems]

As described above, the microwave tube which is the object of the present invention has the electron gun section, the high-frequency circuit section, and the collector section arranged in this order in the tube axis direction, and the electron beam is focused over the entire area of the high-frequency circuit section. It is configured such that it is focused by the magnetic field of the magnetic field device section, passes through the high-frequency circuit section, and is captured by the collector section.

According to the present invention, a ferromagnetic member is symmetrically opposed to a part of the collector core at the front edge of the collector portion in the direction perpendicular to the tube axis, and the opposed ferromagnetic member is magnetized by the magnetic field of the focusing magnetic field device to generate electrons. A reverse deflection magnetic field perpendicular to the beam is formed.

For that purpose, the ferromagnetic member provided in the collector core is brought as close as possible to the high frequency circuit section, and only the non-magnetic member is arranged on the periphery of the ferromagnetic member so that the magnetic field of the focusing magnetic field device section is not shielded.

As a result, it is possible to form a deflection magnetic field having a sufficient strength perpendicular to the electron beam.

[Action]

As shown in FIG. 2, the deflection magnetic field is generated as vertical magnetic fields in mutually opposite directions from the tube axis, and it is possible to prevent retrograde electrons to the high-frequency circuit section which is the object of the present invention.

〔Example〕

Hereinafter, as an embodiment of the present invention, a case of utilizing a magnetic field of a focusing magnetic field device will be described with reference to the drawings. First
The figure is a longitudinal sectional view in the tube axis direction, and FIG. 2 is a sectional view taken along the line AA 'in FIG.

The microwave tube consists of an electron gun section 1, a high frequency circuit section 2, and
A collector unit 4 is arranged. A focusing magnetic field device unit 3 is provided over the entire area so as to cover the high-frequency circuit unit 2 and focuses the electron beam emitted from the electron gun unit 1. The high-frequency circuit section 2 receives the electron beam as an electron beam having a velocity distribution in the high-frequency circuit section 2 and enters the collector section 4.

In this example, the collector portion 4 is an integral type, and the copper collector core 5 is arranged in the vicinity of the high frequency circuit portion 2 by the insulating ring 6, and the front edge portion of the collector core 5 is arranged as shown in FIG. Further, a ferromagnetic member 7 made of iron or the like is provided so as to be symmetrically opposed to and perpendicular to the tube axis. Since the ferromagnetic member 7 is close to the high-frequency circuit unit 2, it is magnetized by the magnetic field of the focusing magnetic field device unit 3, and the magnetic field lines pass through the ferromagnetic member 7 as shown in FIG. 2 in the direction perpendicular to the tube axis. A sufficiently strong magnetic field is generated. Since the potential of the collector portion 4 is lowered, a part of the electron beam not captured by the collector core 5 or secondary electrons generated on the inner surface of the collector core 5 are electrons which go backward to the high frequency circuit portion 2 having a higher potential. Is bent by the magnetic field in the direction perpendicular to the tube axis generated at the front edge of the collector portion 4 in the reverse path, and is captured again by the collector core 5.

〔The invention's effect〕

As described above, in the present invention, at the entrance of the collector portion, the sufficiently strong deflection magnetic field generated in the surface inside the collector core perpendicular to the tube axis acts on the return electrons and secondary electrons from the inside of the collector core. Thus, backflow to the high frequency circuit section is effectively prevented. Therefore, the potential of the collector core can be made sufficiently lower than the potential of the high frequency circuit section, and the power consumption can be greatly reduced.

[Brief description of drawings]

FIG. 1 and FIG. 2 show an embodiment of the present invention, and are a vertical sectional view and a sectional view taken along the line AA in the tube axis direction, respectively. 1 ... Electron gun part, 2 ... High frequency circuit part, 3 ... Focusing magnetic field device part, 4 ... Collector part, 5 ... Collector core, 6 ...
… Insulating ring, 7… Ferromagnetic material,

Claims (1)

[Claims] 1. An electron gun section, a high-frequency circuit section, and a collector section are sequentially arranged in the tube axis direction, and an electron beam is focused by a magnetic field of a focusing magnetic field apparatus section provided over the entire area of the high-frequency circuit section, whereby the high-frequency circuit section is formed. In a microwave tube configured to pass through and be trapped by the collector, a part of the front edge of the collector core of the collector part is provided with ferromagnetic members symmetrically opposed to each other in the direction perpendicular to the tube axis, A microwave tube characterized in that the opposing ferromagnetic members are magnetized by the magnetic field of the focusing magnetic field device to form deflection magnetic fields perpendicular to the electron beam in mutually opposite directions.